Non-contact seals are known in the art and generally fall into categories of labyrinth, hybrid labyrinth, and centrifugal pressure seals. Such seals are used to keep lubricating fluids in a rotatable shaft bearing, and may also keep foreign contaminants out of the environment of a rotating shaft.
An example of a centrifugal pressure seal for roller or ball bearings having a lubricating fluid is found in U.S. Pat. No. 6,170,832 to Ernst. In such a seal a centrifugal pumping chamber pressurizes a portion of the lubricating fluid when the bearing is rotated, and feeds the pressurized lubricating fluid to the bearing to fill the bearing with lubricant or replenish lubricant that has been lost. The seal also is used to prevent contaminants from passing through the seal into the environment of the rotating shaft.
A number of environments that until now could use the advantages of a non-contact seal have not been able to take advantage of the centrifugal pressure seals for various reasons.
For example, the prior art seal in U.S. Pat. No. 6,170,832 is comprised of annular components that require access to the end of a shaft in order to mount or dismount the seal on the shaft. If a gear, sprocket, housing, or bracket is already in place on the shaft, or if other structure blocks the end of the shaft, the seal cannot be mounted on the shaft until the obstructing object is removed. Removal of the obstructing object can be costly and time consuming, or may not be possible at all without destroying other parts of a machine.
It is therefore an object of the present invention to provide a non-contact seal with low friction which can be mounted on a shaft without having access to the end of the shaft. Hence the seal can be mounted at positions intermediate the ends of the shaft.